Greetings Myranda!

I'll relay your request to the development team and let you know what they have to say.

In the mean time, regarding special characters, I can tell you that there are a lot of characters that simply do not exist in Eorzean (writers in the realm have little need for @, $, ~, etc.), so even if we were to release something official, those characters would probably not be included, and have to be replaced with more modern renditions if you were to use the font in-game.

Oh, and by the way, your signature in Eorzean is great!

In case you missed it, here are another few instances of handwritten text.
(Seen in signatures on a photo of Mutamix Bubblypot's Carriers of the Cauldron)